A riveting tool

ABSTRACT

A tool for use in a method of riveting two sheets together using a tubular rivet with an enlarged flange at one end and a mandrel having a shank and a head at one end of the shank with the head being provided with a drill point and comprising the steps of placing the rivet upon the shank of the mandrel and driving the mandrel so that its head pierces an aperture in the sheets to be joined, forcing the rivet into said aperture and then applying a retractive force to the mandrel to withdraw the mandrel and cause its enlarged head to expand the end of the rivet radially outwardly. The tool comprises a body containing a collet for gripping the mandrel, a motor for rotating the collet to drive the mandrel and a pneumatic device to act upon the collet to provide retractive force for withdrawing the mandrel.

United States Patent [72] Inventor Kenneth J. Stokes Kldderminster, England [21] Appl. No. 755,313 [22] Filed Aug. 26, 1968 [45] Patented Dec. 28, 1971 [73] Assignee G.K.N. Screws & Fasteners Limited Smethwlck, Warley, England [32] Priority Aug. 10, 1968 [3 3 Great Britain 38,321/68 [54] RIVETING TOOL 4 Claims, 3 Drawing Figs.

[51] 1nt.Cl. B21j15/18 [50] Field at Search 72/391; 227/51, 52, 53, 55, 58, 59

[56] I References Cited UNITED STATES PATENTS 2,403,675 7/1946 Mitchell 72/391 x Primary ExaminerGranville Y. Custer, Jr. Attorney-Kurt Kelman ABSTRACT: A tool for use in a method of riveting two sheets together using a tubular rivet with an enlarged flange at one end and a mandrel having a shank and a head at one end of the shank with the head being provided with a drill point and comprising the steps of placing the rivet upon the shank of the mandrel and driving the mandrel so that its head pierces an aperture in the sheets to be joined, forcing the rivet into said aperture and then applying a retractive force to the mandrel to withdraw the mandrel and cause its enlarged head to expand the end of the rivet radially outwardly. The tool comprises a body containing a collet for gripping the mandrel, a motor for rotating the collet to drive the mandrel and a pneumatic device to act upon the collet to provide retractive force for withdrawing the mandrel.

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BACKGROUND OF THE INVENTION DESCRIPTION OF THE PRIOR ART Such tubular rivet fastenings as used hitherto have comprised, in combination, a tubular rivet having a tubular body and at one end thereof an enlarged flange or other form of abutment member adapted to engage the exposed face of one .of the sheets to be joined on the front side and a mandrel which is used to insert the rivet through prepared aligned drilled holes in the sheets which are to be joined. In such combination the mandrel has an enlarged head on its forward end and the tubular rivet is positioned behind this head so that the mandrel with the rivet in position can be passed through the prepared holes until the flange or other abutment on the rivet engages the exposed face of one of the sheets to be joined. With the rivet being held against axial withdrawal the mandrel is pulled outwardly through the rivet with the result that the enlarged head of the mandrel engaging the end of the rivet causes this end to expand or bulge outwardly to a transverse dimension greater than the diameter of the prepared hole so as to lock the rivet firmly in position.

Subsequently, the portion of mandrel projecting outwardly from the front of the rivet is broken off or the mandrel may be such that it breaks off under a predetermined tension at a position inside the rivet and the portion of the mandrel left on the blind side may be knocked inwardly so that it drops out of the inner end of the rivet. In some cases the head of the mandrel is so shaped that it locks itself within the expanded wall of the rivet and remains permanently in position when broken away from the remainder. Hitherto, the use of a mandrel and rivet fastening as above-referred-to has required the drilling or punching of the holes in all the sheets being fastened together and this entails the expense of separate preliminary operations and also means that the sheets must be accurately assembled together prior to riveting in order to accurately align the prepared holes in the sheets. This involves the use of jigs and other equipment.

The object of the invention is to provide a riveting tool which will eliminate the aforesaid separate preliminary operations and will facilitate the assembly of the sheets together for the riveting operation without the necessity of jigs or other I equipment.

SUMMARY OF THE INVENTION According to the invention the tool comprises a body having mounted therein a motor rotating a drive shaft, a sleeve which is nonrotatably connected to the drive shaft and capa- BRIEF DESCRIPTION OF THE DRAWINGS One embodiment of the invention is now described in more detail with reference to the accompanying drawings wherein:

FIG. I is a section on the centerline of a tool according to the invention,

FIG. 2 is a section on the line 2-2 of FIG. 1, and

FIG. 3 is a diagrammatic illustration of the pneumatic and fluid pressure circuit connected with the tool shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of tool according to the invention is shown in the figures and is for use with a mandrel having a drilling point and the tool itself is generally in the shape of a gun with a main body part 60 which has formed integrally therewith a hand grip portion 61 and there being a forward body part 62 secured to the part 60 by appropriate screws indicated at 63. Mounted within the main body part 60 is a known form of air turbine motor 64 which has a drive shaft 65 extending from one end thereof and having screw-threaded engagement with a sleeve 66.

Coaxially aligned with the sleeve 66 is a further sleeve 67 which has a counterbore 68 at one end provided with an internal keyway 69 and this end fits over the sleeve 66 which is provided with a number of external keyways 70 so that the keyway 69, upon assembly, can be made to register with one of the keyways 70 in the sleeve 66 and a key 71 inserted so that the sleeve 67 is then nonrotatably connected to the sleeve 66 but is capable of sliding within the body upon the exterior of the sleeve 66.

At its other end the sleeve 67 has a smaller diameter counterbore in which is disposed the one end of a shaft 72 axially aligned with the driving shaft 65 and having its extreme end 73 in screw-threaded engagement with the passage within the sleeve 67 and surrounding the shaft 72 is an external sleeve or tubular member 74 which also has screw-threaded engagement with the counterbore in this end of the sleeve 67.

The shaft 72 extends forwardly through the front body part 62 of the tool towards the nose end 75 of the tool and adjacent its forward end a number of collet fingers 76 are held within an outer collet sleeve 77 rotatably and slidably mounted in this forwardpart of the body of the gun in an internal lining sleeve 78. The collet fingers 76 are spring loaded by a coil spring 79 which is mounted about a reduced diameter portion of the shaft 72 and contained in the annular space between this reduced diameter part of the shaft and the tubular member 74. The member 74 has a radially extending flange 80 bearing against the outer collet sleeve 77 and at its forward end is in screw-threaded engagement with the member 77. A roller bearing assembly 81 is mounted about the member 74 adjacent the flange 80 of this sleeve and the spring 79 bears against a washer 82 which itself bears against the inner ends of the collet fingers 76 to keep these urged forwardly into engagement with the interior of the exterior collet sleeve 77.

A further roller thrust bearing 83 is mounted in the forward nose 75 of the tool and there is also fitted at this end a flanged guide sleeve 84 through which passes the shank 85 of the mandrel with the drill point which is to be used with a rivet to be inserted by the tool and the outer end of this mandrel 85 engages within a counterbore in the forward end of shaft 73 and is gripped so as to hold it firmly in the tool by the collet fingers 76. The other end of the drill mandrel, is provided with any suitable form of drill point.

In a chamber 86, formed in the front body part 62 below the shaft 73, there is pivotally mounted upon a pivot pin 87 a twoarmed lever 88, each arm of which is bifurcated and the upper bifurcated arm 89 engages on opposite sides of the member 74 while one side of the bifurcated arm engages the forward end of the sleeve 67 and the other side of the bifurcated arm engages a plate 90 forming part of the thrust bearing assembly 81.

Housed in the main body part 60 of the tool, below the motor 64, is a fluid pressure piston cylinder'device comprising a cylinder 91 having working therein a piston 92, the piston rod 93 whereof extends outwardly through the forward end 94 of the cylinder and has, at its extreme end, an enlarged head 95 and spaced therefrom an abutment nut 96 which is screwed on to the exterior of the piston rod 93. The other bifurcated arm 97 of the two-armed lever embraces this forward end of the extension of the piston rod and engages between the enlarged head 95 on one side and the abutment nut 96 on the other side. A strong coil spring 98 surrounds the piston rod 93 and urges the piston 92 towards the left hand end of the cylinder, as shown in the drawings, which is the normal position of the tool when being operated for the drill mandrel 85 to drill the hole through the sheets which are being fastened by a rivet.

Referring to FIG. 2, air under pressure from a suitable source of supply is supplied to the handgrip part 61 through a suitable connection 99 and air passes into the chamber 100 in the handgrip part. Mounted in the upper part of the handgrip 61 is a known form of control valve 101 operated by a press button 102 which, when pressed inwardly against the pressure of its spring 103, admits air from the chamber 100 via the passage 104 to operate the air turbine motor 64, causing rotation of the drive shaft 65 and simultaneous rotation therewith of the shaft 72 and thus the mandrel 85 of the drill to drill the required hole through one or more of the sheets being fastened together.

In practice, the supply of compressed air to the tool will be obtained from the normal compressed air supply provided in industrial establishments but this would not be of sufficiently high pressure to operate the piston 92 and provide the necessary force required to withdraw the mandrel 85 through the rivet and cause expansion of the rivet to lock it in position. The much higher pressure required to operate the piston 92 is obtained from a pneumatic/fluid pressure intensifier which is indicated diagrammatically in FIG. 3, which shows diagrammatically the piston 92 and piston rod 93 in the cylinder 91 within the body of the gun and being supplied with fluid under pressure, via the passage 105, through the handgrip part of the body. The intensifier comprises a pneumatic cylinder 106 supplied with air under pressure via the inlet 107 from the same source of supply as supplies the air to the air motor of the tool and the piston 108 of the cylinder has a piston rod 109 extending into a fluid pressure cylinder 110 and constituting the piston of this cylinder 110 which has suitable fluid within its cylinder and supplies the fluid under pressure via a flexible pipe 111 to the passage 105 in the tool.

When it' is desired to operate the piston 92 an air signal from the too] is passed to the intensifier via a flexible pipe 112 which'is adapted to be connected to a suitable connection 113 on the handgrip of the tool communicating with a passage 114 in the handgrip so that air from the chamber 100 passes through the passage 114 and pipe 112 to a known form of signal device 115 which then is operated to admit the air under pressure via inlet 107 to the cylinder 106 of the intensifier thus causing fluid under pressure considerably higher than that of the air inlet pressure to be forced into the cylinder 91 in the tool and thus operate the piston 92 to move this forwardly in its cylinder against the pressure of its restraining spring 98.

The air signal to operate the intensifier is sent from the tool by operation of the known form of control valve 116 cmbodied in the upper part of the handgrip and operated by a press button 117 which, when depressed, admits air from the chamber 100 in the handgrip via a passage 118 into the valve and through a passage 119, in the piston of the valve, to the passage 114 and thus to the flexible pipe 112 and the signal device 115.

Thus, after the motor 64 has been operated to rotate the mandrel 85 of the drill and drill the required hole, the forward pressure exerted by the operator on the gun causes the nose end thereof to push the rivet through the hole formed in the sheets to be secured until the flange 85b on the rivet engages the forward side of such sheets. The nose end 75 of the tool is maintained in contact with the flange b. Then the control button 117 is operated to cause. as above described, the piston 92 to move forwardly in its cylinder with the result that the double arm lever 88 is pivoted in the anticlockwise direction as seen in FIG. 1 so that the sleeve 67 is moved to the left in FIG. 1, sliding over the sleeve 66 and causing the collet fingers and collet sleeve to pull the mandrel rearwardly. Because the nose end 75 of the tool is in contact with the flange 85b, the rivet itself cannot be pulled out of the hole formed in the sheets and the reaction of the force exerted by the collet in pulling the mandrel rearwardly is transmitted to the flange 85b through the nose end 75. Thus the rearward movement of the collet fingers and sleeve cause the enlarged drill head of the mandrel to be moved back through the rivet, causing expansion of the wall of the rivet on the blind side of the sheets and firmly anchoring the rivet in position. If the mandrel is provided with a weakened neck portion adjacent the drill head then, upon a predetermined tension being achieved in the shank 85 of the mandrel, this will break off at the said weakened section, leaving the head of the drill to drop out of the blind side of the work, or, if desired, to remain sealed in position within the tubular rivet.

What we then claim is:

1. A tool for riveting two sheets together comprising a body having mounted therein a motor rotating a drive shaft, a sleeve which is nonrotatably connected to the drive shaft and capable of axial sliding movement in the body relatively to the drive shaft in the axial direction thereof, a collet device adapted to grip one end of a mandrel, slidably and rotatably mounted in the body and connected to said sleeve so as to be rotated therebyand moved axially therewith, a fluid pressure piston and cylinder unit mounted in said body of the tool and means connecting the piston of said unit with said sleeve whereby axial movement of the piston, within its cylinder, produces axial sliding movement of said sleeve.

2. A tool according to claim 1 wherein the piston and cylinder unit is housed in the body, in substantially side-byside relationship with the motor, the piston having a piston rod connected thereto and extending axially from one end of the cylinder, and the means connecting the piston with said sleeve comprises a two-armed lever pivoted in the body with one arm of the lever engaging said sleeve and the other arm engaging the end of the piston rod.

3. A tool according to claim 2 wherein the collet device includes an elongated member one end of which is fixed within the end of said sleeve which is furthest from the motor and the other end of which member engages within an external collet sleeve of the collet device and the one arm of said two-armed lever which engages the said sleeve also engages, on its opposite side, said collet sleeve, the piston of said piston and cylinder unit being spring urged in one direction in its cylinder which pivots the two-arm lever in the direction to move the said collet sleeve in the outwards direction.

4. A tool according to claim 1, wherein the motor is operated by compressed air, the supply of which to the motor is controlled by a manually operable valve in the body of the tool wherein the piston and cylinder unit is operated by fluid at higher pressure than said compressed air, said fluid being supplied from a fluid pressure intensifier having a pneumatic cylinder, the piston of which has a piston rod extending into a fluid-filled cylinder and acting as the piston therein, and said pneumatic cylinder having an air supply controlled by valve means which is operated by an air signal derived from the compressed air supply to the tool and controlled by a further manually operable valve in the body of the tool. 

1. A tool for riveting two sheets together comprising a body having mounted therein a motor rotating a drive shaft, a sleeve which is nonrotatably connected to the drive shaft and capable of axial sliding movement in the body relatively to the drive shaft in the axial direction thereof, a collet device adapted to grip one end of a mandrel, slidably and rotatably mounted in the body and connected to said sleeve so as to be rotated thereby and moved axially therewith, a fluid pressure piston and cylinder unit mounted in said body of the tool and means connecting the piston of said unit with said sleeve whereby axial movement of the piston, within its cylinder, produces axial sliding movement of said sleeve.
 2. A tool according to claim 1 wherein the piston and cylinder unit is housed in the body, in substantially side-by-side relationship with the motor, the piston having a piston rod connected thereto and extending axially from one end of the cylinder, and the means connecting the piston with said sleeve comprises a two-armed lever pivoted in the body with one arm of the lever engaging said sleeve and the other arm engaging the end of the piston rod.
 3. A tool according to claim 2 wherein the collet device includes an elongated member, one end of which is fixed within the end of said sleeve which is furthest from the motor and the other end of which member engages within an external collet sleeve of the collet device and the one aRm of said two-armed lever which engages the said sleeve also engages, on its opposite side, said collet sleeve, the piston of said piston and cylinder unit being spring urged in one direction in its cylinder which pivots the two-arm lever in the direction to move the said collet sleeve in the outwards direction.
 4. A tool according to claim 1, wherein the motor is operated by compressed air, the supply of which to the motor is controlled by a manually operable valve in the body of the tool wherein the piston and cylinder unit is operated by fluid at higher pressure than said compressed air, said fluid being supplied from a fluid pressure intensifier having a pneumatic cylinder, the piston of which has a piston rod extending into a fluid-filled cylinder and acting as the piston therein, and said pneumatic cylinder having an air supply controlled by valve means which is operated by an air signal derived from the compressed air supply to the tool and controlled by a further manually operable valve in the body of the tool. 